1. Technical Field
The invention relates generally to a semiconductor device and a programming method thereof, and more particularly, to a semiconductor device having a three-dimensional (3D) structure and a programming method thereof.
2. Related Art
A semiconductor device typically includes a memory cell array configured to store data, a program associated with the memory cell array, a peripheral circuit configured to perform read and erase operations, and a control circuit for controlling the peripheral circuit.
Examples of semiconductor devices include, but are not limited to, two-dimensional (2D) semiconductor devices and three-dimensional (3D) semiconductor devices. In a 2D semiconductor device, the memory cells are arranged in a generally parallel configuration on a semiconductor substrate, In a 3D semiconductor device, the memory cells are arranged in a generally perpendicular configuration on a semiconductor substrate.
In a 3D semiconductor device, the memory cell array typically includes a plurality of memory blocks. Each of the memory blocks is includes a plurality of vertical strings arranged in a generally perpendicular configuration with respect to the semiconductor substrate. The vertical strings include a vertical channel film. The vertical channel film is surrounded by a tunnel insulating film. The tunnel insulating film is surrounded by a memory film. The memory film includes a charge storage film. The charge storage film extends vertically along the tunnel insulating film A plurality of of word lines are spaced apart from each other vertically along the charge storage film in a stacked configuration.
While a configuration of a 3D semiconductor device has been described above, the 3 semiconductor device may have alternative configurations. The other configurations also typically include the vertically extending charge storage film and vertically spaced apart word lines in a stacked configuration.
A programming operation of the 3D semiconductor device is typically performed in the manner described below.
When a programming voltage of a relatively higher voltage is applied to a selected word line, charge is trapped in a memory cell electrically coupled to the selected word line. Charge is typically trapped in a charge storage film where the selected word line is formed.
Since the charge storage film extends vertically, the trapped charge may be move to an upper portion or a lower portion due to a relative difference in the density of the charge trapped in the charge storage film.